Coalescing Filters

Model: DD390

Core Technical Specifications

Filter Grade: DD Primary Coarse Coalescing Pre-Filtration

Filtration Precision: 1 μm solid particles, bulk condensed water & large liquid oil droplets

Residual Oil Mist at Outlet: ≤0.5 ppm under rated airflow

Filter Media: Multi-layer gradient HV borosilicate micro glass fiber with permanent hydrophobic & oleophobic coating

Rated Matching Airflow Capacity: 390 m³/min

Max Working Pressure: 16 bar / 232 PSIG

Max Continuous Operating Temperature: ≤66℃

Service Life Standard: 4000–8000 working hours OR 12 months, whichever comes first; replace if differential pressure hits 0.35 bar

Airflow Direction: Outside-to-Inside

Key Product Features

Frontline Barrier Protection for Entire Air System

Serves as the first purification stage of compressed air pipeline system. It intercepts pipeline rust, scale, workshop dust, massive condensate and bulky oil droplets. It drastically cuts contaminant load on downstream PD390 superfine and QD390 activated carbon filter cartridges, extends their service cycles and prevents premature oil saturation of refrigerated dryer desiccant media.

Low Pressure Drop & Energy Saving

Deep-pleated glass fiber media maximizes effective filtration area. It maintains stable low airflow resistance under 24-hour full-load continuous operation, reduces extra power consumption of air compressors and lowers overall factory air supply operating costs.

Ultra-Large Dirt & Liquid Holding Capacity

Multi-gradient layered depth filtration structure stores massive separated lubricating oil, condensed water and solid sludge contaminants, greatly extending maintenance intervals and minimizing production downtime during filter replacement.

Heavy-Duty Stainless Steel Reinforced Support Cage

Dual stainless steel mesh cages resist strong high-speed airflow impact under heavy-duty industrial conditions, preventing filter media collapse, deformation and fiber shedding to eliminate secondary fiber contamination of clean compressed air.

Working Principle

Raw unpurified compressed air flows into the cartridge from the outer stainless steel protective mesh. The outer coarse fiber layer traps large solid particles, liquid water and bulky oil droplets; minor oil mist is coalesced into heavy liquid condensate, which sinks to the filter housing bottom and drains automatically by gravity. Primarily purified compressed air flows to PD390 superfine coalescing filter for further trace oil mist removal.

Application & Industries

First-stage protective pre-filter for medium-flow industrial compressed air post-processing systems, installed upstream of superfine coalescing filters and refrigerated air dryers.

Widely applied in general machinery manufacturing, automotive production lines, packaging printing industrial parks, textile factories, conventional industrial spraying, large pneumatic tool stations, food primary processing, medium-heavy laser cutting and factory centralized compressed air supply systems.